Flexible connectors are known in the art. Examples of various connectors can be found in U.S. Pat. Nos. 2,010,546; 2,273,395; 2,657,076; 2,836,436; 3,528,260; 3,788,394; 4,408,467; 4,480,857; 4,793,150 and 5,048,873.
In a typical automobile air conditioning system presently in use, refrigerant is conveyed by flexible hoses and rigid tubing to the compressor, the condenser and the evaporator. The flexible hoses and rigid tubing accommodate the vibration and movement existing between the vehicle frame, upon which the condenser and evaporator are rigidly affixed, and the vehicle engine upon which the compressor is rigidly affixed.
Refrigerant utilized in automobile air conditioning systems has historically been a chloroflourocarbon (CFC). More recently, hydroflourocarbon (HFC) refrigerant has been adopted and is expected to replace CFC refrigerant as the dominant refrigerant used in such systems. HFC refrigerant is extremely expensive, much more expensive than CFC refrigerant. However, with progressive taxation recently placed on CFC refrigerant, its cost will similarly rise. Further, CFC refrigerants have been found to be detrimental to the environment if released into the atmosphere. Accordingly, it is important that air conditioning systems used in vehicles be designed to prevent, to the greatest degree possible, any escape of CFC and HFC refrigerants into the atmosphere. The challenge to develop such a system has intensified because flexible hose assemblies presently used to convey refrigerant through the system often permit refrigerant loss by effusion through the hose wall and end fitting connection sites.
Flexible hoses presently used in air conditioning systems permit variable levels of moisture ingression which over time greatly reduces the efficiency of the system. Flexible hoses are also subject to twisting during installation, which not only causes premature wear, but also places undesirable stresses and potential failure and leakage at the fittings fastening such hoses to system elements. In contrast, rigid lengths of tubing formed of any one of a wide variety of materials are capable of transporting refrigerant throughout the air conditioning system without effusion of refrigerant or infusion of undesirable moisture through the conduit walls. For example, the tubing may be formed of metal such as aluminum, steel or a variety of other metals. However, aluminum is preferred from the standpoint of minimizing weight. Additionally, the tubing may be formed of a wide variety of plastics. In order to utilize rigid lengths of tubing for conveying the refrigerant in an air conditioning system of a vehicle, while providing a system with adequate flexibility, it is necessary that the rigid lengths of tubing include flexible connectors that permit pivotal, articulating, and/or rotational movement of one tube section length relative to another.
As is well known in the art, refrigerant in the air conditioning system of a vehicle is transported under varying pressures including pressures potentially as high as 500 pounds per square inch (psi). Accordingly, it is necessary that any connectors for connecting lengths of tubing have adequate means, for sealing therebetween, to prevent or at least minimize the leakage of refrigerant. As may be appreciated, the challenge is to provide a flexible connector assembly for fastening together the rigid tubing lengths so that there is no appreciable loss of refrigerant from or infusion of moisture into an air conditioning system.